bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3    Contributed by Axis Communications AB.
   4    Written by Hans-Peter Nilsson.
   5
   6 This file is part of BFD, the Binary File Descriptor library.
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 /* See info in the file PORTING for documentation of these macros and
  23    functions.  Beware; some of the information there is outdated.  */
  24
  25 #define N_HEADER_IN_TEXT(x) 0
  26 #define BYTES_IN_WORD 4
  27 #define N_TXTOFF(x) 32
  28 #define ENTRY_CAN_BE_ZERO
  29 #define TEXT_START_ADDR 0
  30
  31 /* Without reading symbols to get the text start symbol, there is no way
  32    to know where the text segment starts in an a.out file.  Defaulting to
  33    anything as constant as TEXT_START_ADDR is bad.  But we can guess from
  34    the entry point, which is usually within the first 64k of the text
  35    segment.  We also assume here that the text segment is 64k-aligned.
  36    FIXME: It is also wrong to assume that data and bss follow immediately
  37    after text, but with those, we don't have any choice besides reading
  38    symbol info, and luckily there's no pressing need for correctness for
  39    those vma:s at this time.  */
  40 #define N_TXTADDR(x) ((x).a_entry & ~0xffff)
  41
  42 /* If you change this to 4, you can not link to an address N*4+2.  */
  43 #define SEGMENT_SIZE 2
  44
  45 /* For some reason, if the a.out file has Z_MAGIC, then
  46    adata(abfd).exec_bytes_size is not used, but rather
  47    adata(abfd).zmagic_disk_block_size, even though the exec_header is
  48    *not* included in the text segment.  A simple workaround is to
  49    #define ZMAGIC_DISK_BLOCK_SIZE, which is used if defined; otherwise
  50    TARGET_PAGE_SIZE is used.  */
  51 #define ZMAGIC_DISK_BLOCK_SIZE N_TXTOFF (0)
  52
  53 /* It seems odd at first to set a page-size this low, but gives greater
  54    freedom in where things can be linked.  The drawback is that you have
  55    to set alignment and padding in linker scripts.  */
  56 #define TARGET_PAGE_SIZE SEGMENT_SIZE
  57 #define TARGETNAME "a.out-cris"
  58
  59 /* N_SHARED_LIB gets this reasonable default as of 1999-07-12, but we
  60    have to work with 2.9.1.  Note that N_SHARED_LIB is used in a
  61    SUN-specific context, not applicable to CRIS.  */
  62 #define N_SHARED_LIB(x) 0
  63
  64 /* The definition here seems not used; just provided as a convention.  */
  65 #define DEFAULT_ARCH bfd_arch_cris
  66
  67 /* ??? Spacing might be essential for the parameters in this macro.
  68    Do Not Change.  */
  69 #define MY(OP) CAT (cris_aout_,OP)
  70 #define NAME(x,y) CAT3(cris_aout,_32_,y)
  71
  72 #include "bfd.h"
  73
  74 /* Version 1 of the header.  */
  75 #define MY_exec_hdr_flags 1
  76
  77 #define MY_write_object_contents MY(write_object_contents)
  78 static boolean MY(write_object_contents) PARAMS ((bfd *));
  79
  80 /* Forward this, so we can use a pointer to it in PARAMS.  */
  81 struct reloc_ext_external;
  82
  83 #define MY_swap_ext_reloc_out MY(swap_ext_reloc_out)
  84 static void MY(swap_ext_reloc_out) PARAMS ((bfd *, arelent *,
  85                                             struct reloc_ext_external *));
  86
  87 #define MY_swap_ext_reloc_in MY(swap_ext_reloc_in)
  88 static void MY(swap_ext_reloc_in) PARAMS ((bfd *, struct
  89                                            reloc_ext_external *,
  90                                            arelent *, asymbol **,
  91                                            bfd_size_type));
  92
  93 #define MY_set_sizes MY(set_sizes)
  94 static boolean MY(set_sizes) PARAMS ((bfd *));
  95
  96 /* To set back reloc_size to ext, we make MY(set_sizes) be called
  97    through this construct.  Note that MY_set_arch_mach is only called
  98    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  99    not call set_sizes.  */
 100
 101 #define MY_set_arch_mach NAME (aout, set_arch_mach)
 102 #define SET_ARCH_MACH(BFD, EXEC) \
 103  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXEC))
 104
 105 /* These macros describe the binary layout of the reloc information we
 106    use in a file.  */
 107 #define RELOC_EXT_BITS_EXTERN_LITTLE 0x80
 108 #define RELOC_EXT_BITS_TYPE_LITTLE 3
 109 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 110
 111 #ifndef MY_get_section_contents
 112 #define MY_get_section_contents aout_32_get_section_contents
 113 #endif
 114
 115 /* Include generic functions (some are overridden above).  */
 116 #include "aout32.c"
 117 #include "aout-target.h"
 118
 119 /* We need our own version to set header flags.  */
 120
 121 static boolean
 122 MY(write_object_contents) (abfd)
 123      bfd *abfd;
 124 {
 125   struct external_exec exec_bytes;
 126   struct internal_exec *execp = exec_hdr (abfd);
 127
 128   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 129      seems unnecessary when inspecting as and ld behavior (not an
 130      exhaustive inspection).  The default write_object_contents
 131      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 132   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 133
 134   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 135      the default definition.  */
 136   if (bfd_get_arch(abfd) == bfd_arch_cris)
 137     N_SET_MACHTYPE(*execp, M_CRIS);
 138
 139   N_SET_FLAGS (*execp, aout_backend_info (abfd)->exec_hdr_flags);
 140
 141   WRITE_HEADERS (abfd, execp);
 142
 143   return true;
 144 }
 145
 146 /* We need our own for these reasons:
 147    - Assert that a normal 8, 16 or 32 reloc is output.
 148    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 149
 150 static void
 151 MY(swap_ext_reloc_out) (abfd, g, natptr)
 152      bfd *abfd;
 153      arelent *g;
 154      struct reloc_ext_external *natptr;
 155 {
 156   int r_index;
 157   int r_extern;
 158   unsigned int r_type;
 159   unsigned int r_addend;
 160   asymbol *sym = *(g->sym_ptr_ptr);
 161   asection *output_section = sym->section->output_section;
 162
 163   PUT_WORD (abfd, g->address, natptr->r_address);
 164
 165   r_type = (unsigned int) g->howto->type;
 166
 167   r_addend = g->addend;
 168   if ((sym->flags & BSF_SECTION_SYM) != 0)
 169     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 170
 171   /* If this relocation is relative to a symbol then set the
 172      r_index to the symbols index, and the r_extern bit.
 173
 174      Absolute symbols can come in in two ways, either as an offset
 175      from the abs section, or as a symbol which has an abs value.
 176      check for that here.  */
 177
 178   if (bfd_is_abs_section (bfd_get_section (sym)))
 179     {
 180       r_extern = 0;
 181       r_index = N_ABS;
 182     }
 183   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 184     {
 185       if (bfd_is_und_section (bfd_get_section (sym))
 186           /* Remember to check for weak symbols; they count as global.  */
 187           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 188         r_extern = 1;
 189       else
 190         r_extern = 0;
 191       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 192     }
 193   else
 194     {
 195       /* Just an ordinary section.  */
 196       r_extern = 0;
 197       r_index = output_section->target_index;
 198     }
 199
 200   /* The relocation type is the same as the canonical ones, but only
 201      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 202      We may change this later, but assert this for the moment.  */
 203   if (r_type > 2)
 204     {
 205       (*_bfd_error_handler) (_("%s: Invalid relocation type exported: %d"),
 206                              bfd_get_filename (abfd), r_type);
 207
 208       bfd_set_error (bfd_error_wrong_format);
 209     }
 210
 211   /* Now the fun stuff.  */
 212   natptr->r_index[2] = r_index >> 16;
 213   natptr->r_index[1] = r_index >> 8;
 214   natptr->r_index[0] = r_index;
 215   natptr->r_type[0] =
 216      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 217       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 218
 219   PUT_WORD (abfd, r_addend, natptr->r_addend);
 220 }
 221
 222 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 223
 224 static void
 225 MY(swap_ext_reloc_in) (abfd, bytes, cache_ptr, symbols, symcount)
 226      bfd *abfd;
 227      struct reloc_ext_external *bytes;
 228      arelent *cache_ptr;
 229      asymbol **symbols;
 230      bfd_size_type symcount;
 231 {
 232   unsigned int r_index;
 233   int r_extern;
 234   unsigned int r_type;
 235   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 236
 237   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 238
 239   /* Now the fun stuff.  */
 240   r_index =  (bytes->r_index[2] << 16)
 241     | (bytes->r_index[1] << 8)
 242     |  bytes->r_index[0];
 243   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 244   r_type = ((bytes->r_type[0]) >> RELOC_EXT_BITS_TYPE_SH_LITTLE)
 245     & RELOC_EXT_BITS_TYPE_LITTLE;
 246
 247   if (r_type > 2)
 248     {
 249       (*_bfd_error_handler) (_("%s: Invalid relocation type imported: %d"),
 250                              bfd_get_filename (abfd), r_type);
 251
 252       bfd_set_error(bfd_error_wrong_format);
 253     }
 254
 255   cache_ptr->howto =  howto_table_ext + r_type;
 256
 257   if (r_extern && r_index > symcount)
 258     {
 259       (*_bfd_error_handler)
 260         (_("%s: Bad relocation record imported: %d"),
 261          bfd_get_filename (abfd), r_index);
 262
 263       bfd_set_error (bfd_error_wrong_format);
 264
 265       /* We continue, so we can catch further errors.  */
 266       r_extern = 0;
 267       r_index = N_ABS;
 268     }
 269
 270   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 271      default.  */
 272   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 273 }
 274
 275 /* We use the same as the default, except that we also set
 276    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 277    NAME (aout, set_arch_mach) in aoutx.  */
 278
 279 static boolean
 280 MY(set_sizes) (abfd)
 281      bfd *abfd;
 282 {
 283   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 284
 285   adata(abfd).page_size = TARGET_PAGE_SIZE;
 286   adata(abfd).segment_size = SEGMENT_SIZE;
 287   adata(abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 288   adata(abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 289
 290   /* ... except for that we have the extended reloc.  The alternative
 291      would be to add a check on bfd_arch_cris in NAME (aout,
 292      set_arch_mach) in aoutx.h, but I don't want to do that since
 293      target-specific things should not be added there.  */
 294
 295   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 296
 297   return true;
 298 }
 299
 300 /*
 301  * Local variables:
 302  * eval: (c-set-style "gnu")
 303  * indent-tabs-mode: t
 304  * End:
 305  */